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Water Scarcity and Water Productivity

 

In principle, increasing water use efficiency raises the returns to water use. In practice, the data are complex and difficult to interpret, especially in systems other than crop production.

 
 

 

OVERVIEW

Findings

The CPWF was launched to address a problem perceived to be of global importance: water scarcity. The expected solution to water scarcity was improved agricultural water productivity, defined as agricultural output per unit of water depleted. Agricultural output could be measured as physical yields or value of production for individual crops, multiple cropping, or livestock or fisheries. It was understood that higher water productivity was essential for improvements in food security and livelihoods. As the program unfolded and experience was gained, however, we realized that things weren’t that simple.

Water scarcity

Is water scarce? It depends. In some parts of some basins, per capita water available for direct consumption is below minimum thresholds. There are also places where surface water (“blue water”) is not sufficient for all desired uses: agriculture, fisheries, mining, hydropower, recreation, domestic and industrial use, and the provision of ecosystem services. On the other hand, even in dry river basins, only a small fraction of rainfall (“green water”) goes through agricultural systems. Most rainfall runs off, evaporates, percolates into groundwater, or is transpired by plants outside of agricultural systems. In these basins, there can be scarcity in the midst of plenty.

We found that water scarcity has many dimensions. Even in seemingly water-abundant locations, water was often saline or polluted; inadequate (drought) or excessive (floods); available too early or too late; or inaccessible to users.

Blue water is only physically scarce in selected areas. Problems with water quality and lack of investment in water technology are far more pervasive. The abundance of green water is typically ignored. Institutions and governance are central to dealing with issues of water quality, access, and infrastructure investment – and therefore central to dealing with issues of water scarcity.

Water productivity

Originally, an important objective of the CPWF was to raise water productivity. We found that water productivity can be a useful diagnostic, especially when combined with other productivity measures, but has limited value as a standalone objective.

Water productivity is defined as output per unit of water depleted. In several projects, we estimated the water productivity of irrigated crops in terms of grain production (kg) per unit of irrigation water applied (m3). Often, however, we found that estimating both numerator (output) and denominator (water depleted) was tricky.  Output was sometimes estimated as value of production for multiple cropping, and sometimes as physical yield or value of production for livestock or fisheries. One project developed a conceptual framework for measuring livestock water productivity, showing that water for feed and fodder was typically the most important factor.

Water depletion could rarely be measured directly. Approximations such as rainfall or actual evapotranspiration were sometimes used. Different measures and units were used at different scales. All of this made it very difficult to make systematic water productivity comparisons across enterprises, locations, scales, or over time.

In principle, increasing water use efficiency raises the returns to water use. In practice, however, the data are complex and difficult to interpret, especially in systems other than crop production.

Examples

The Andes team found that in many small river basins, water pollution is more of a problem than physical water scarcity. Highland mining can affect large numbers of downstream water users. Downstream water quality can also deteriorate because open grazing of fragile alpine wetlands or hillside cropping without the use of soil conserving practices.

The Limpopo team found that seasonal unreliability of rainfall was even more of a problem than low average rainfall levels. More often than not, the rainy season would start late, or finish early, or have dry spells during the season. Years with severe flooding would alternate with years too dry for cropping.

In the Volta, thousands of small reservoirs help harvest rainfall for later use. These reservoirs help address issues of seasonal unreliability of rainfall but have their own problems with regard to access and water quality. The Volta team worked with communities on small reservoir governance and the use of reservoir water for farm system intensification.

A project in the Ganges was able to improve aquaculture in seasonally flooded areas of Bangladesh – but community groups interested in aquaculture must compete with private investors to lease seasonally flooded areas. Access to water, not its physical scarcity, is the issue.

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PUBLICATIONS

Performance of innovation platforms in crop-livestock agro-ecosystems of the Volta basin in Burkina Faso (Paper)



A paper on how the CPWF Volta project on integrated management of rainwater in crop-livestock systems (V2) adopted an overarching innovation platform approach that supports learning and exchange for action research and for scaling up and out of promising best-fit rainwater management strategies.

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Special Issue: Water, Food and Poverty in River Basins, Part 1



While water scarcity is a convenient focus of attention, the reality is far more complex than ‘less water means more poverty’. Evidence from river basins reveals that while water scarcity is a serious issue in some basins, it is not the only, or even the major, water-related constraint to development. Other factors include the sharing of resources; vulnerability to hazard and ability to construct and support highly productive systems.

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Limpopo River Basin: Thirst for Growth (Magazine feature)



This issue of AgriDeal magazine features five stories that provide an overview of the Limpopo River basin; its agriculture, water and development challenges; and how the LBDC is working to improve integrated management of rainwater within the basin. - See more at: /basins/limpopo-2/#sthash.oQT6VfR5.dpuf

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Valeurs d’usage ou performances techniques: comment apprécier le rôle des petits barrages en Afrique subsaharienne? (Paper)



This paper proposes an analytical framework to understand why small reservoirs remain popular on the agendas of national policy-makers and international development partners in sub-Saharan Africa despite of recurrent analyses highlighting that these systems function well below the expectations of their promoters.

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Institutional arrangements in seasonal floodplain management under community-based aquaculture in Bangladesh (Journal article)



Seasonal floodplains under private and public ownership in the Indo-Ganges river basin provide food and income for millions of people in Bangladesh. Floodplain ownership regimes are diverse, covering the whole spectrum from public to private ownership. The paper compares community-based fish culture projects in these floodplains and analyzes the institutional arrangements of three different Floodplain Management Committees.

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Opportunity in Adversity: Collective Fish Culture in the Seasonal Floodplains of Bangladesh (Outcome story)



Past efforts to increase the productivity of seasonal floodplains have focused primarily on increasing water productivity during the dry season, when farmers are able to plant food crops. This project looked at how to increase floodplain productivity during the wet season through the use of community-based fish culture.

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STORIES & NEWS

Is the glass half empty or full? Unpacking water scarcity



CPWF’s book entitled Water, Food and Poverty in River Basins: Defining the Limits challenges the conventional wisdom that as global population increases the demands on food and water systems will inevitably push ten of the world’s major river basins over the edge and lead to a major world water crisis. CPWF research has found that overall these basins are capable of supporting populations in 2050, particularly if productivity of rain-fed systems is increased. However, the path to sustainability depends on appropriate policies and institutions.

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Water scarcity or inequitable access to water resources?



During the past 50 years, development pressures on natural resources have grown to such an extent that they are challenging the effectiveness of conventional planning and decision-making. A new ‘nexus’ approach is needed, one that better understands the inter-dependencies across water, energy and food—an approach that identifies mutually beneficial responses and provides an informed and transparent framework for determining benefits and risks. This is the challenge for our world today.

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Mining in the Andes: an economic and environmental stalemate?



The relationship between mining and the quantity and quality of the water in the Andean region is complex. Balancing the economic impetus of mining with socially and environmentally sustainable development is a key challenge and is closely related to CPWF’s Andes Basin Development Challenge – to increase water productivity and reduce water-related conflict through the establishment of equitable benefit-sharing mechanisms.

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OUTPUTS & TOOLS

The CompAndes Negotiation Support System



The CompAndes Negotiation Support System is a test bed for negotiations around benefit-sharing mechanisms for water focusing on sustaining equitable flows of water for all through appropriate land, ecosystem, and water management.

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Seven lessons learned to catalyze African innovation through engagement platforms



This brief presents lessons learned on the use of engagement platforms, which are also known as multi-stakeholder platforms or innovation platforms. In general terms, an engagement platform is an opportunity for individuals and people representing organizations with different backgrounds and interests to come together to diagnose problems, identify opportunities and implement solutions.

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What is a Benefit Sharing Mechanism?



This flier outlines what a benefit-sharing mechanism is and why such mechanisms are needed in the Andean region.

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Small Reservoirs Toolkit



This toolkit provides information on approximately 30 tools and techniques presented in four topic areas: i) Intervention Planning; ii) Storage and Hydrology; iii) Ecosystems and Health; iv) Institutions and Economics. This tool kit is intended for the use of NGOs, research institutes, universities, donor agencies, multilateral organizations, and government agencies.

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Identifying Strategies for Increasing Livestock Water Productivity in the Blue Nile Basin



The livestock sector is socially and politically very significant in developing countries because it provides food and income for one billion of the world’s poor, especially in dry areas, where livestock keeping is often the only source of livelihoods. One CPWF project in the Nile saw the need to develop strategies to improve livestock water productivity.

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LEARN MORE

  • Alemaw, B.F, K Scott, and A. Sullivan. 2010. Water availability and access in the Limpopo Basin. In Working Paper: Basin Focal Project series, BFP-L01. Colombo, Sri Lanka: Challenge Programme on Water and Food (CPWF).
  • Cai, X., D. Molden, M. Mainuddin, B. Sharma, Mobin-ud-Din Ahmad, and P. Karimi. 2011.
  • Cook, SE, MJ Fisher, L. Harrington, A Huber-Lee, and A Vidal. 2009.
  • Harrington, L., S.E. Cook, J. Lemoalle, M. Kirby, C. Taylor, and J. Woolley. 2009.
  • Molden, D., T. Oweis, P. Steduto, P. Bindraban, M.A. Hanjra, and J. Kijne. 2010.
  • Mulligan, M., L.L.S. Cruz, J. Pena-Arancibia, B. Pandey, G. Mahé, and M. Fisher. 2011.
  • Peden, D. 2008. Could 150 million thirsty livestock be efficient water harvesters? Nile Basin studies show how. In Collective Action News, Issue No. 4, November 2008: Alliance of the CGIAR Centers.
  • Vidal, A., L. Harrington, and M. Fisher. 2014 (in press).